Casting molds

ABSTRACT

A novel mold for making castings of metal or other molten material is provided with a vertical main sprue having gating or feeder lines radiating outwardly and extending downwardly at an angle from said main sprue to one or more mold cavities, the novel inclined arrangement of said feeder lines causing molten metal introduced into said mold cavities to be trapped therein and permitting the immediate evacuation of the metal from said main sprue after said cavities have been filled.

United States Patent Samuel G. MacNeill Milwaukee;

Henry L. Eickelberg, Watertown, both of Wis.

Oct. 23, 1968 Dec. 21, 1971 Modern Equipment Company Port Washington, Wis.

[72] Inventors Appl. No. Filed Patented Asaignee CASTING MOLDS 2 Claims, 7 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 1,797,041 3/1931 Becker 164/309 2,195,960 4/1940 Morris 164/336 2,852,822 9/1958 Strom 164/306 X 3,523,570 8/1970 Groteke et al.. 164/119 1,797,041 3/1931 Becker 164/309 2,875,485 3/1959 Schneider... 164/35 X 2,912,728 11/1959 Sylvester 164/309 X 3,329,201 7/1967 Miller .1 164/309 FOREIGN PATENTS 1,041,549 5/1953 France 164/34 381,363 10/1964 Switzerland 164/129 Primary Examiner-J. Spencer Overholser Assistant Examiner-John E. Roethe Attorney-Morsell & Morsell ABSTRACT: A novel mold for making castings of metal or other molten material is provided with a vertical main sprue having gating or feeder lines radiating; outwardly and extending downwardly at an angle from said main sprue to one or more mold cavities, the novel inclined arrangement of said feeder lines causing molten metal introduced into said mold cavities to be trapped therein and permitting the immediate evacuation of the metal from said maiin sprue after said cavities have been tilled.

SHEET 1 0F 2 \NVENTORS SAMUEL (5. Mac NElLL HENRY L. EICKELBERG ATTORNEYS WWW mm m SHEET 2 BF 2 INVENTORS SAMUEL (3. Mac NEILL HENRY L. EICKELBERG ATTORNEYS CASTING MOLDS BACKGROUND OF THE INVENTION I. Field of the Invention The present invention is concerned with the casting of molten material, especially metal, and relates more particularly to an improved gating arrangement for molds.

2. Description of the Prior Art In the casting of metal and other molten materials a common practice is to form a mold including a top section, or socalled cope, and a bottom section, or drag, with the mold cavity or cavities formed therebetween and with a main vertical sprue having feeder lines or so-called gates extending horizontally outwardly to said cavities. In the casting operation the molten metal is introduced into the main sprue and flows laterally outwardly through said horizontal feeder lines to the mold cavities, where it solidifies to form the castings. To prevent the metal from flowing back out of said cavities before the casting has had an opportunity to harden it is necessary to maintain the sprue and feeder lines in such conventional mold units full of molten metal until the casting has formed. Unfortunately, the column of metal in said main sprue also solidifies, of course, and must be remelted for subsequent castings, which remelting operation is time consuming, inefficient and relatively costly.

SUMMARY OF THE INVENTION The present invention provides a new and improved mold gating arrangement including a main vertical sprue with radiating feeder lines extending downwardly at an angle therefrom to the mold cavity or cavities in a manner whereby molten metal is trapped within said cavities and cannot escape therefrom, thus making it unnecessary to maintain metal in the main sprue while the casting solidifies. The result is that with the present invention the metal in the sprue can be returned to the furnace or ladle in its molten state and does not have to be remelted for subsequent castings, thereby providing maximum yield for the volume of metal melted and substantially increasing the efficiency and economy of the casting operation.

A further object of the invention is to provide an improved mold gating arrangement eliminating the necessity for continuously remelting the sprue metal, as described, which innovation permits the use of automatic, high-speed equipment in many casting operations heretofore performed manually.

A further object of the present invention is to provide a new and improved casting mold arrangement wherein the elimination of a solidified metal column in the main sprue avoids the necessity for shearing the finished castings therefrom, as in conventional molds of the same general type, thereby speeding and facilitating the production of the castings.

A further object of the present invention is to provide a new and improved mold and gating arrangement which can be utilized with various methods and systems of introducing the molten metal into the mold, including pneumatic pressure or vacuum-type filling apparatuses.

Still further objects of the present invention are to provide a new and improved mold arrangement for the purposes described which is simple in design and operation, which is reliable, and which is otherwise particularly well adapted for its intended purposes.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, illustrating several forms of mold units coming within the intended scope of the present invention, and wherein the same reference numerals designate the same or similar parts in all of the views:

FIG. 1 is a vertical sectional view of a pressurized ladle and mold unit showing the mold prior to filling;

FIG. 2 is a similar sectional view of the unit of FIG. 1 showing the mold as it is filled with molten metal;

FIG. 3 is a similar view illustrating the unit after the metal has been evacuated from the main sprue;

FIG. 4 is a vertical sectional view of a modified, multiplemold unit within the scope of the invention;

FIG. 5 is a vertical sectional view of another modified mold arrangement employing a tiltable pouring ladle, showing the unit prior to filling;

FIG. 6 is another view of the mold unit illustrated in FIG. 5 showing the mold being filled; and

FIG. 7 is a similar view showing the mold unit of FIGS. 5 and 6 with the mold cavities filled and the main sprue evacuated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularly to FIGS. 1-3 of the drawings, illustrated therein is a pressurized vessel 10 in the form of a ladle or furnace, and including a top cover 11 with an opening through which a vertical fill tube 12 is inserted into the vessel interior. A gasket 13 and suitable clamping means (not shown) provide an airtight seal between said vessel and the cover 11, and a gas line 14 is provided adjacent the top of said vessel, said line being connected to a suitable source of air or other gas under pressure. A quantity of molten metal 16, or other molten material to be cast, is carried in said vessel and maintained at a level substantially above the lower end of the vertical fill tube 12.

Seated on the vessel cover 11 is a mold 17 formed of dry or green sand or other suitable material, and including a permanent-type mold if desired. Said mold 17 includes a cope I8 and drag l9 defined by a parting line 20, the mold cavity 21 being formed therebetween as is well known in the foundry art. A main sprue 22 extends vertically through said mold, opening in both the top and bottom thereof, and is positioned in registration with the aforementioned fill tube 12 extending downwardly into the molten metal vessel. Radiating outwardly from said main sprue 22 to the mold cavity 21 is the gating consisting of one or more feeder lines 23. In accordance with the present invention, and unlike conventional molds wherein the feeder lines are disposed substantially horizontally, said feeder lines 23 are angled downwardly from the main sprue to the mold cavity, the communication between said feeder lines and the sprue being above the highest point of said mold cavity. This is a critical feature of the present invention, as will be seen in the following operational description.

In the type of pneumatic filling apparatus illustrated in FIGS. 1-3 sufficient molten metal 16 (or other material) is initially provided in the ladle or furnace 10 to cover a substantial portion of the downwardly extending fill tube 12, as described, and when it is desired to fill the mold cavity air or other gas under pressure is introduced into said vessel 10 through the inlet 14. Said gas bears downwardly IIIPOII the surface of the molten metal 16 in the vessel, as indicated diagrammatically by the arrows in FIG. 2, and functions to force said metal up wardly in the feeder tube 12 and into the aligned main sprue 22 in the mold. Sufficient gas pressure is applied in said vessel 10 to force the molten metal 16 upwardly in the mold sprue to a point where said metal enters the communicating feeder lines 23, and runs down said inclined feeder lines to fill the mold cavity 21.

As will be readily appreciated, due to the inclined nature of the feeder lines 23 and the fact that said feeder lines communicate with the main sprue at a point above the highest point of the mold cavity, the molten metal 16 is trapped within said mold cavity 21 and cannot run back out through the gating. Thus it is unnecessary to maintain metal in the sprue 22 until the casting has solidified in order to prevent the metal from escaping the mold cavity, and the pressure in the vessel can be released to allow the metal in said sprue to drain back into the vessel (FIG. 3). The result is that in the present invention the metal in the main sprue does not solidify therein, as in conventional molds having noninclined feeder lines and which necessitates the costly and time-consuming remelting of said sprue metal for use in succeeding castings.

In the operation of a foundry it is critical that for a given weight of metal melted the yield, or ratio of metal thatis actually used in the castings, be as high as possible in order to ensure the most efficient and economical operation possible. In this respect the present invention is a definite improvement over prior casting operations wherein the sprue metal solidifies in each casting cycle and must be repeatedly remelted. In actual practice the melting of said sprue metal is just as costly as the melting of the metal utilized in each casting. In addition, it frequently happens that when the metal is remelted the chemical composition thereof is altered, particularly in the case of alloys, and must be metallurgically replenished each time, which is also time consuming and costly.

A further important advantage of the present invention is that with the use of the improved gating arrangement, wherein the necessity for remelting the sprue metal after each casting cycle is eliminated, high-speed, pressure-type automatic casting equipment can be used for many casting operations heretofore performed manually, such as the precision casting of relatively small parts, or so-called investment casting. As will be readily appreciated, the automation of the casting operation allows substantial cost savings, and is an important development in the art.

Further, by draining the main sprue before the metal has an opportunity to harden therein eliminates the necessity for detaching the finished castings from a metal column, which is time consuming. Rather, in the present invention it is merely necessary to sever the relatively short length of hardened filler line metal from the casting.

In FIG. 4 of the drawings there is illustrated a modified mold arrangement that can be utilized within the scope of the present invention. In this multitiered unit a plurality of individual molds 17 are arranged in stacked relation with their main sprues 22 aligned with each other and with the feeder tube I2 of the furnace or other pressurized vessel 10, and with the gating 23 in said molds inclined, as shown. Thus there is provided an arrangement similar to that hereinabove described but whereby a plurality of molds can be filled in each casting cycle, thereby promoting high volume casting operations.

With respect to the molds illustrated in FIGS. 1-4, incidentally, it is to be understood that the mold cavities 21 can be of any desired shape or configuration, including suitable risers and vents for the escape of gas, and said molds can be formed of sand or any other desired material without departing from the intended scope of the invention. Moreover, the particular metal-pouring system utilized is not critical and the invention is by no means to be limited or confined to a pressure-type filling operation such as that illustrated and' hereinabove described. It is contemplated, for example, that a vacuum could be employed to draw the molten metal upwardly in the main sprue in lieu of the illustrated pneumatic apparatus, or the mold could be mechanically lowered into and then raised from the molten bath in order to fill the cavities. In addition, a simple tiltable ladle-type filling apparatus could be used, as will now be described.

With reference to FIGS. -7 of the drawings, illustrated therein is a nonsymmetrical mold 27 of the type frequently used for casting a plurality of small metal parts. Said mold includes a main sprue 28 having branchlike gating elements 29, 30, 31, and 32 radiating outwardly and downwardly therefrom, each of said branch elements including a mold cavity 33 and an inclined feeder line 34 communicating with said sprue at a point above said cavity. The upper end 35 of said mold unit 27 is enlarged and outwardly flared, as shown, while the lower end of said mold unit is provided with a restricted orifice 36 of reduced diameter.

In the use of the mold unit 27, and referring now to FIGS. 5 and 6, the molten metal 16 is poured from a ladle or furnace 39 or the like into the enlarged upper end 35 of the mold. A portion of said metal passes directly downwardly through the vertical sprue 28 and out through the bottom opening 36, but because said orifice is of a relatively small diameter and the metal is introduced at the top at a faster rate than it escapes from said lower end the sprue fills with metal. When the level of the metal in the sprue reaches the gating members 29-32 said molten metal travels downwardly and laterally outwardly in the feeder lines 34 to fill the mold cavities 33. Due to the inclined nature of said feeder lines the molten metal is trapped within said mold cavities and cannot escape therefrom. The metal in the sprue continues to drain through the bottom opening 36, where it is caught in a ladle 40 or other suitable receptacle, and thus said metal does not solidify in the sprue, as in conventional molds.

In lieu of having the bottom orifice 36 open to permit the continuous evacuation of metal from the sprue during the filling operation a plug or closure (not shown) can be employed to close off the mold lower end during filling, said closure being removed as soon as the mold cavities are filled in order to permit the drainage of the metal from the sprue while it is still in a molten state. It is also contemplated that in some instances it might be desirable to maintain the metal in the sprue until a thin shell forms on the periphery thereof, the sprue then being drained and leaving said shell as a supplemental means of ensuring that the molten metal does not escape from the mold cavities.

From the foregoing detailed description it will be seen that the present invention provides a novel mold gating arrangement for making castings of metal or other molten material which is an improvement over the molds heretofore used. In accordance with the present invention the mold vertical sprue is provided with radiating feeder lines extending downwardly at an angle to the mold cavity or cavities in a manner whereby molten metal introduced into the mold is trapped within said cavities and cannot run back out through the feeder lines. This is unlike conventional molds having horizontal feeder lines and wherein the sprue must be maintained in a full condition until the metal in the mold cavity has solidified. Thus in the present invention the metal in the sprue can be evacuated in its molten state for immediate reuse, and it is unnecessary to tediously remelt said sprue metal for succeeding castings. The result is maximum yield for a given weight of metal melted. In addition, because of the elimination of the necessity for remelting the sprue metal the present invention permits the use of automatic, high-speed, pressure-type casting apparatuses in many instances where such automation has heretofore been unfeasible.

It is to be understood thatwhile several preferred mold designs coming within the scope of the present invention have been illustrated and described herein, various other modified mold forms can also be employed and the invention is not to be limited or confined in this respect. What is intended to be covered herein are the several fonns of the invention disclosed and also any and all variations or modifications thereof as may come within the spirit of said invention, and within the scope of the following claims.

What we claim is:

1. In a casting mold having a mold cavity therein, the improved combination sprue and gating arrangement, comprising: an upright sprue in said mold, the lower end of which sprue opens in the bottom of the mold and the upper end of which sprue is open at the top of the mold; means positionable above said mold for pouring molten material into the open top of said sprue; and an inclined feeder line in said mold communicating with said sprue and extending downwardly and laterally outwardly therefrom to said mold cavity with at least a portion of said feeder line located above the highest point of said mold cavity, said inclined feeder line arrangement being adapted to trap molten material introduced therein through said sprue and feeder line within said mold cavity, and the open lower end of said sprue permitting molten material in said sprue to drain therefrom after said cavity has been filled.

2. The mold recited in claim 1 wherein the opening at the lower end of said sprue is of lesser size than the sprue top opening to promote the filling of said sprue and cavity. 

1. In a casting mold having a mold cavity therein, the improved combination sprue and gating arrangement, comprising: an upright sprue in said mold, the lower end of which sprue opens in the bottom of the mold and the upper end of which sprue is open at the top of the mold; means positionable above said mold for pouring molten material into the open top of said sprue; and an inclined feeder line in said mold communicating with said sprue and extending downwardly and laterally outwardly therefrom to said mold cavity with at least a portion of said feeder line located above the highest point of said mold cavity, said inclined feeder line arrangement being adapted to trap molten material introduced therein through said sprue and feeder line within said mold cavity, and the open lower end of said sprue permitting molten material in said sprue to drain therefrom after said cavity has been filled.
 2. The mold recited in claim 1 wherein the opening at the lower end of said sprue is of lesser size than the sprue top opening to promote the filling of said sprue and cavity. 